Manufacture of footwear



June 6, 1967 1%. s. GOY 3,324,220

MANUFACTURE OF FOOTWEAR Filed Oct. 28, 1964 2 Sheets-Sheet 1 Inuanlwr p nd/o1 Sfang/[e/c/ 60/ 5 /2122, 1/22 222- 22222,)

June 6, 1967 R. s. GOY 3,324,220

MANUFACTURE OF FOOTWEAR Filed Oct. 28, 1964 2 Sheets-Sheet 2 v F 545%), MM, M2

,LYZornm/s v United States Patent 3,324,220 MANUFACTURE OF FOOTWEAR Ronald Stansfield Goy, Sutton Coldfield, England, assignor to Dunlop Rubber Company Limited, London, England, a British company Filed Oct. 28, 1964, Ser. No. 407,093 Claims priority, application Great Britain, Nov. 6, 1963, 43,745/ 63 14 Claims. (Cl. 264-244) This invention relates to the manufacture of footwear and particularly to a method for the manufacture of footwear having a textile reinforcement coated with a flexible material.

According to the present invention a method for the manufacture of footwear having a textile reinforcement coated with a flexible material comprises placing the textile reinforcement over a shaping former, said reinforcement being formed of shrinkable yarns and in its unshrunk state enclosing said former without distortion of the reinforcement, shrinking the reinforcement to be a tight fit on said shaping former to produce a consolidation of the reinforcement and covering the reinforcement with the flexible material.

The present invention provides a method of forming footwear in which the flexible material does not penetrate the textile reinforcement to a substantial extent or cause any folding or creasing of the reinforcement durnig and after application of the flexible material. Hitherto, it has been usual to prepare the textile reinforcement and to stretch it over the shaping former, with the result that at the wide parts of the shaping former distortion of the reinforcement has occurred and an opening of the structure so produced has permitted an excessive degree of strike-throng or penetration of the flexible material through the reinforcement. The textile reinforcement of the present invention is formed to be of such a shape as to cover the widest part of the shaping former without distortion and after shrinking the reinforcement is a tight fit on the shaping former without distortion or opening of the interstices between the individual yarns forming the reinforcement and thus is substantially unpenetrable to the flexible material.

The method is particularly useful for the manufacture of footwear in the form of boots in which the reinforcement is in the form of a sock which can be knitted and which, in the footwear, forms not only the textile reinforcement but a lining for the boot. The invention is particularly suitable for the formation of boots having uppers which extend over the ankles and upwards towards the knee of the wearer, such as those commonly known as Wellington boots. The textile reinforcement is formed from shrinkable yarns and these are yarns which preferably have a high potential shrinkage and are preferably shrinkable by the application of heat or heat and moisture. Typical yarns which can be employed are those based on polyamides, polyesters such as polyethylene glycol terephthalate, or blends of such yarns or polyvinyl chloride yarns with viscose yarns. High shrinkage can be induced in thermoplastic yarns by stretching prior to blending or knitting at a temperature lower than that subsequently used for heat-shrinking. All viscose or cotton yarns can be shrunk by slack mercerisation.

The flexible material that forms the surface of the footwear can be any natural or synthetic rubber or flexible synthetic plastic material and typical flexible materials which can be used are natural rubber, copolymers of butadiene and styrene, polybutadiene, cis-polyisoprene, and polyvinyl chloride. The method of application of the flexible materials to the reinforcement carried on the shaping former depends to some extent on the particular flexible material being used and the type of footwear being produced, but where convenient it is preferred to use an injection or compression moulding technique. In the case of injection moulding of plastic material this can be carried out using a cool mould in the known manner. In the case of compression moulding the reinforcement is covered with the flexible material in sheet form and the assembly so formed is moulded in a suitable shaped mould. Another method of application of the flexible material is dipping.

The method of the invention provides a convenient method for the manufacture of footwear which reduces the likelihood of strike-through or creasing of the flexible material. This is particularly important in all moulding techniques. The textile reinforcement can be formed in a variety of ways and when knitted, a variety of stitch formations can be employed so producing attractive and comfortable inner linings for the footwear. The particular shape of the shaping former, i.e., the last, will depend on the particular article of footwear to be manufactured.

One method for the manufacture of a boot in accordance with the invention will now be described by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a section of a sock to be employed in the manufacture of a boot,

FIG. 2 is a section of the sock shown in FIGURE 1 positioned on a last prior to shrinking,

FIG. 3 is a section through the assembled sock and last after shrinking, and

FIG. 4 is a section through the sock and last when positioned in a mould.

A sock 1 was knitted with one end of 10s cotton count rayon yarn and one end of denier polyvinyl chloride yarn with 35 courses per inch and 21 wales per inch. To illustrate the shrinkability of the sock a second sock having the same construction as sock 1 was heated for 5 seconds in hot air at 220 C. and the diameter was reduced by 25 percent and the length by 30 percent.

The sock 1 was fitted over a last 2 having the shape of a Wellington boot and the sock 1 was of a size such that it was a loose fit over the last 2 including the calf region 3 of the last 2. The last 2 is a solid metal last having a stepped extension portion 4 at its end remote from the foot region for locating the last within a mould. The sock 1 in position on the last 2 as shown in FIG- URE 2 was heated in hot air until the sock shrunk to be a close fit on the last 2, as shown in FIGURE 3.

Calendered sheets of a natural rubber composition 5 were then placed on the surface of the sock 1 with fillings and sole blank 6 on the foot portion 7 and the assembly inserted in a mould 8. The mould 8 consists of two halves 9 one of which is only shown in FIGURE 4, the other half has been removed. The parting plane of the mould halves is as shown at 10. The mould is provided with a stepped portion 11 to engage the stepped portion 4 on the last, and a sole plate 12 carries the sole pattern for the boot. After closing the mould it is subjected to heat and pressure to consolidate the assembly and to vulcanize the rubber composition. Rubber was substantially prevented from penetrating the sock 1 during moulding and no creasing or folding of the sock 1 took place. After vulcanization the completed boot was removed from the mould with the sock 1 forming the lining and the reinforcement.

Having now described my invention-what I claim is:

1. A method for the manufacture of footwear having a textile reinforcement coated with a flexible material which comprises placing the textile reinforcement over a shaping forimer, said reinforcement being formed of shrinkable yarns and in its unshrunk state having substantially the shape of the former but being a loose fit thereon, enclosing said former without distortion of the reinforcement, shrinking the reinforcement to be a tight fit on said shaping former to produce a consolidation of the reinforcement, and covering the reinforcement with a flexible material.

2. A method according to claim 1 in which the textile reinforcement is formed of yarns having a high potential shrinkage.

3. A method according to claim 1 in which the yarns are shrinkable by the application of heat.

4. A method according to claim 1 in which the yarns are shrinkable by heat and moisture.

5. A method according to claim 1 in which the yarns are caused to be shrinkable by stretching prior to blending or knitting at a temperature lower than that used subsequently for heat-shrinking.

6. A method according to claim 1 in which the textile reinforcement is in the form of a knitted sock.

7. A method according to claim 1 in which the reinforcement is formed from polyamide yarns.

8. A method according to claim 1 in which the reinforcement is formed of polyester yarns.

9. A method according to claim 1 in which the reinforcement is formed of a blend of polyester yarns with viscose yarns.

10. A method according to claim 1 in which the reinforcement is formed of a blend of polyvinyl chloride yarns with viscose yarns.

11. A method according to claim 1 in which the textile reinforcement, after shrinking to be a tight fit on the shaping former, is covered with a vulcanizablc natural or synthetic rubber composition and placed in a compression mould to eifect vulcanization of the composition.

12. A method according to claim 11 in which the synthetic rubber composition comprises a copolymer of butadiene and styrene.

13. A method according to claim 11 in which the synthetic rubber composition comprises a copolymer of polybutadiene.

14. A method according to claim 11 in which the synthetic rubber composition comprises synthetic cis-polyisoprene.

References Cited UNITED STATES PATENTS 2,356,948 8/1944 Reed 264257 X 2,357,360 9/ 1944 Rollmann 264244 FOREIGN PATENTS 1,271,522 8/1961 France.

ROBERT F. WHITE, Primary Examiner.

T. J. CARVIS, Assistant Examiner. 

1. A METHOD FOR THE MANUFACTURE OF FOOTWEAR HAVING A TEXTILE REINFORCEMENT COATED WITH A FLEXIBLE MATERIAL WHICH COMPRISES PLACING THE TEXTILE REINFORCEMENT OVER A SHAPING FORMER, SAID REINFORCEMENT BEING FORMED OF SHRINKABLE YARNS AND IN ITS UNSHRUNK STATE HAVING SUBSTANTIALLY THE SHAPE OF THE FORMER BUT BEING A LOOSE FIT THEREON, ENCLOSING SAID FORMER WITHOUT DISTORTION OF THE REINFORCEMENT, SHRINKING THE REINFORCEMENT TO BE A TIGHT FIT ON SAID SHAPING FORMER TO PRODUCE A CONSOLIDATION OF THE REINFORCEMENT, AND COVERING THE REINFORCEMENT WITH A FLEXIBLE MATERIAL. 